Refrigerator evaporator



Ap 1.933. c. STEENSTRUP REFRIGERATOR EVAPORATOR Original Filed Aug. '28, 1929 Invent or- 1 Christian Steenstrup,

His Attorneg.

Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE CHRISTIAN STEENSTRUP, OF SCHEN'ECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK REFRIGERATOR EVAPORATOR Application filed August 28, 1929, Serial No. 389,049. Renewed August 31, 1932.

My invention relates to refrigerator cvaporators, and has for its object the provision of an evaporator which can be readily fabricated from metal plates and which is entirely free from recesses and crevices, so

that it can be easily cleaned. Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to form part of this specification.

In the drawing, Fig. 1 is a perspective view of a refrigerator cabinet having a compression refrigerating system which includes an evaporator made in accordance with my invention; Fig. 2 is a plan view of my improved evaporator partly broken away;

Fig. 3 is a sectional view on the line 33 of Fig. 2; Fig. 4 is a sectional view on the line 44 of Fig. 3; Fig. 5 is a fragmentary section on the line 5-5 of Fig. 3; and Fig.

6 is a fragmentary section on the line 6-6 of Fig. 3 showing the charging valve of the evaporators.

Referring to the drawing, the evaporator, which I have illustrated as indicating one manner of carrying out my invention, includes a top plate 10 providing a flat upper surface on the evaporator for supporting several ice trays in direct contact with the same, so as to facilitate freezing water in the ice trays or other articles placed thereon.

The flat plate 10 is turned downwardly about 35 theouter edge thereof as indicated at 11,

and this downturned edge abuts an upturned edge 12 of bottom plate 13, the edges 11 and 12 being jointed together by brazing, or in any other suitable manner. The space between the plates 10 and 13 is divided into a refrigerant chamber 14 and a chamber 15 by a partition wall- 16. The outer edge of the partition wall 16 is turned upwardly, as indicated at 16', and is secured to the turned over edges 11 and 12 of the top and bottom plates of the evaporator.

In order to avoid any recesses or crevices on the outer surface of the evaporator, which I would be difficult to clean, in accordance 0D with my invention, a header 17 of the evaporator is made by forming a recess 18 along one edge of the plate 10, to constitute the header for refrigerant, communicating directly with the chamber 14. The evaporator 1S initially charged with refrigerant through a valve 17' in the header. During the operation of the machine, refrigerant is supplied to the evaporator through pipe 19 connected to the header, and the refrigerant level is maintained in the header 17 6o slightly below the outlet 20 shown in Fig. 1, through which the vaporized refrigerant is withdrawn from the header by the compressor of the refrigerating system associated with the evaporator. By maintaining the level of the refrigerant in the header 17 slightly below the outlet 20, liquid refrigerant is maintained directly in contact with the surface of the top plate 10, and the refrigerant can freely circulate over the inner surface of the top plate 10 to the header 17 so as to quickly freeze any object placed on the top plate, and to effectively cool the cabinet.

In this evaporator, I have made the refrigerant chamber 14 directly under the top plate 10, so as to obtain a rapid transfer of heat from articles placed onthe top plate to the refrigerant. It is to be noted, however, that when comparatively warm articles are placed on the top plate there will be a considerable increase in load on the refrigerating machine, until the article is frozen or its temperature is reduced to substantially that of the evaporator. In accordance with my invention, the increase in loadon the refrigerating machine due to this cause is lessened by extending aportion of the chamber 15 containing a salt solution or the like constituting the heat absorbin body into contact with the top plate 10 o the evaporator. This maybe done in any convenient manner, but I prefer to do it by forming hollow protuberances on the partition wall 16, which are in close contact with the inner surface of the top plate 10. In the present construction, I do this by pro viding perforations 21in the partition 16, having inverted cups 22 secured therein which are brazed to the inner surface of the 10 top plate as indicated at 23, so as to obtain good thermal conductivity between them. The inverted cups 22 are attached to the bottom plate 13 and communicate with the chamber 15, containing the heat absorbing solution, through notches 24 formed in the side walls thereof below the partition 16. As the cups 22 are secured to the top and bottom plates of the evaporator they reinforce the structure and prevent the plates being separated by the pressure of the refrigerant. It will be apparent, that when a warm object is placed on the top plate 10, the heat absorbing capacity of the solution in the chamber 15, which is in direct communication with the inverted cups 22, greatly facilitates lowering the temperature of theobject placed on the top plate, because the heat absorbing solutioncirculates through the inverted cups 22, which are in good thermal contact with the top plate 10, so that it supplements the heat absorbing capacity of the refrigerant in the chamber 14. The chamber 15 is initially filledwith the heat absorbing solution through the Valve 15.

It is desirable to provide for continuous circulation of refrigerant between the header 17 and the refrigerant chamber 14, so as to remove vaporized refrigerant from the inner surface of the top plate 10 as rapidly as it is vaporized. If this is not done, the accumulation of vaporized refrigerant on the inner surface of the top plate 10 will impair the conduction of heat between t top plate and the refrigerant and thereby reduce the effective surface of the eva orator. I therefore provide a plurality o baffies 25 extending from the header 17 adjacent the opposite side of the chamber 14, but in spaced relation thereto, so as to permit the circulation of refrigerant about the ends of the baflles. These baflies are inclined upwardly from the header toward the opposite edge of the evaporator, and are supported on the partition wall 16 by down turned edges 26. It will thus be seen that the baflles provide for the circulation from the header 17 about the baffles of liquid refrigerant flowing beneath the baffles to the edge of the evaporator opposite the header and thence beneath the top plate 10 to the header. This carries vaporized refrigerant from the surface beneath the top plate to the header as rapidly as it is vaporized, and thereby prevents the accumulation of refrigerant vapor on the surface of the plate, which would impair conduction of heat from the top plate to the refrigerant, and also effectively cools the evaporator.

In order to control the refrigerating system associated with the evaporator in accordance with the temperature of the evaporator, so as to maintain the desired temperature in the cabinet'in which the evap- 1,904.,aeo

orator is used, I arrange a pipe 27 in the chamber 15 below the partition wall 16, which is closed at one end at 28 and extends through the partition wall and the top of the header as indicated at 29 and 30 respectively. A suitable thermostatic tube is placed in this pipe, which controls the refrigerating system in the usual manner.

In using my improved evaporator in connection with the refrigerator cabinet as shown in Fig. 1, I prefer to arrange the evaporator with the header 17 at the back of the cabinet 31 and support the evaporator in substantially horizontal position adjacent the top of the. refrigerator cabinet on rods 32 which are attached to cars 33 secured to the edge of the evaporator. Condensed refrigerant is supplied to the evaporator and vaporized refrigerant is withdrawn therefrom by the refrigerating machine indicated at 34 having a control device 35 for starting and stopping the machine of the system in accordance with the temperature of the evaporator.

Modifications of the particular construction of the evaporator which I have disclosed will occur to those skilled in the art, so that l do not desire my invention to be limited to the particular construction set forth, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States 1s:

1. An evaporator for refrigerating machines includin a top plate for supporting articles to be frozen, another plate joined to said top plate to form a refrigerant chamber, said top plate having a recess therein to constitute a header for the refrigerant chamber, and a baffle extending between said plat'es from said header adjacent the opposite edge thereof.

2. An evaporator for refrigerating machines including a top plate for supporting articles to be frozen, and another plate joined to said top plate to form a refrl erant chamber, and a bottom plate secure to said plates to form a chamber for a heat absorbing body, said top plate having a recess therein to constitute a header for the refrigerant chamber.

3. An eva orator for refrigerating machines inclu mg a top plate for supportin articles to be frozen, another plate joined to said top plate to form a refrigerant chamber, means cooperating with said other plate for providing a chamber for a heat absorbing body, and heat conducting means extending from said other plate to said top plate.

4. An evaporator for refrigerating ma chines including a top plate for supporting articles to be frozen, another plate joined to said top plate to form a refrigerant chamber, and means cooperating with said other plate for providing a chamber for a heat absorbing body, said other plate having hollow protuberances extending into contact with said top plate and communicating with said chamber for the heat absorbing body.

5. An evaporator for refrigerating machines including a flat top plate for supporting articles to be frozen, another plate joined to said top plate to form a refrigerant chamber, said top plate having a recess constituting a header for the refrigerant chamber, and means cooperating with said other plate for providing a chamber for a heat absorbing body, said other plate having hollow protuberances extending into contact with said top plate and communicating with said chamber for the heat absorbing body.

6. An evaporator for refrigerating machines including a flat top plate for supporting articles to be frozen, a bottom plate spaced from the top plate, and a partition between said plates dividing the space between them into a refrigerant chamber and a chamber for heat absorbing material, said partition having hollow protuberances extending into contact with said top plate and communicating with the chamber for the heat absorbing body.

An evaporator for refrigerating machines including a fiat top plate for supporting articles to be frozen, a bottom plate spaced from said top plate, and a partition between said plates dividing the space between them into a refrigerant chamber and a chamber for a heat absorbing body, said partition being perforated and having cupshaped parts secured in the perforations in said their ttoms secured to said top plate and communicating with said chamber for the heat absorbing body.

8. An evaporator for refrigerating machines including a flat top plate for supporting articles to be frozen, a bottom late spaced from said top plate, and a partition between said plates dividing the space between them into a refrigerant chamber and a chamber for a heat absorbing body, said partition being perforated and having cupshaped parts secured in the perforations, said cup-shaped parts having their bottoms secured to said top plate and the mouths thereof secured to said bottom plate and communicating with said chamber for the heat absorbing body.

9. An evaporator for refrigerating machines including a flat top plate for supporting articles to be frozen, a bottom plate spaced from said top plate, said plates having turned over edges abutting each other, and a partition between said plates dividlate, said cup-shaped parts having ing the space between them into a refrigerant chamber and a chamber for a heat absorbing body, said partition having turned over edges fitting the turned over edges of said top and bottom plates.

10. An evaporator for refrigerating machines including a flat top plate for supporting articles to be frozen, a bottom plate spaced from said top plate, said plates having turned over edges abutting each other, and a partition between said plates dividing the space between them into a refrigerant chamber and a chamber for a heat absorbing body, said top plate being formed with a recess along one edge thereof to constitute a header for said refrigerant chamher, said partition having turned over edges fitting the turned over edges of said top and bottom plates and being provided with hollow protuberances extending to said top. plate and communicating with the chamber for the heat absorbing body.

11. In combination with a refrigerator cabinet, an evaporator arranged therein to constitute a shelf, said evaporator including a top plate for supporting articles to be frozen and another plate joined to said top plate to form a. refrigerant chamber, and a bottom plate secured to said plates to form a chamber for a heat absorbing body, said top plate having a recess therein to constitute a header for the refrigerant chamber.-

12. In combination with a refrigerator cabinet, an evaporator arranged therein to constitute a shelf, said evaporator including a flat top plate for supportingarticles to be frozen, another plate joined to said top plate to form a refrigerant chamber, and means cooperating with said plate for providing a chamber for a heat absorbing body, said other plate having hollow protuberances extending into contact with said top plate and communicating with said chamber for the heat absorbing body.

In,witness whereof, I have hereunto set my hand this 27th day of August, 1929.

CHRISTIAN STEENSTRUP. 

